TY - JOUR
T1 - Isolation of new photoadducts from UVA-irradiated N-nitrosoproline with 2'-deoxyadenosine and characterization of photoadducts from DNA irradiated with N-nitrosoproline
AU - Asahi, Chiharu
AU - Aoyama, Shuhei
AU - Kimura, Sachiko
AU - Suzuki, Toshinori
AU - Hatano, Tsutomu
AU - Arimoto-Kobayashi, Sakae
N1 - Funding Information:
This work was supported by JSPS KAKENHI [Grant Number JP15K00556 ]; the NIBB Cooperative Research Program for the Okazaki Large Spectrograph [Grant Number 19-701 & 18-707 ]; and funding from The Okayama Medical Foundation .
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/9/1
Y1 - 2020/9/1
N2 - N-nitrosoproline (NPRO) is formed from nitrosation of proline and has been reported to be non-carcinogenic and non-mutagenic. However, earlier studies in our laboratory showed that pre-irradiated NPRO can be converted to a mutagenic form. We previously investigated the reaction of NPRO with dA or dG under UVA irradiation and identified the formation of 2-pyrrolidyl-dA adducts (P1 & P2) and 8-pyrrolidyl-dG adducts (G1 & G2) as well as four known modified nucleosides, although several peaks found in the HPLC profiles of UVA-irradiated mixtures of dA and NPRO remain unidentified. In the present study we isolated new photoproducts from irradiated mixtures of dA and NPRO and identified (R)- and (S)-8-(2-pyrrolidyl)-2′-deoxyadenosine (A1 and A2) as products by MS and NMR. We also investigated the photoadducts formed in DNA treated with NPRO under UVA irradiation, and detected A1 and/or A2 (probably both), P1, P2, G1 and/or G2, and 8-oxodG as products. Under anaerobic conditions, formation of A1 and A2 was greater than that under aerobic conditions, suggesting that photo-reactions comprising pyrrolidyl radical with dA may increase under anaerobic conditions given reduced competition with oxidative photo-reactions which may decompose pyrrolidyl-dA adducts.
AB - N-nitrosoproline (NPRO) is formed from nitrosation of proline and has been reported to be non-carcinogenic and non-mutagenic. However, earlier studies in our laboratory showed that pre-irradiated NPRO can be converted to a mutagenic form. We previously investigated the reaction of NPRO with dA or dG under UVA irradiation and identified the formation of 2-pyrrolidyl-dA adducts (P1 & P2) and 8-pyrrolidyl-dG adducts (G1 & G2) as well as four known modified nucleosides, although several peaks found in the HPLC profiles of UVA-irradiated mixtures of dA and NPRO remain unidentified. In the present study we isolated new photoproducts from irradiated mixtures of dA and NPRO and identified (R)- and (S)-8-(2-pyrrolidyl)-2′-deoxyadenosine (A1 and A2) as products by MS and NMR. We also investigated the photoadducts formed in DNA treated with NPRO under UVA irradiation, and detected A1 and/or A2 (probably both), P1, P2, G1 and/or G2, and 8-oxodG as products. Under anaerobic conditions, formation of A1 and A2 was greater than that under aerobic conditions, suggesting that photo-reactions comprising pyrrolidyl radical with dA may increase under anaerobic conditions given reduced competition with oxidative photo-reactions which may decompose pyrrolidyl-dA adducts.
KW - Adenine adduct
KW - DNA adduct
KW - N-nitrosoproline
KW - Photoreaction
KW - Reactive oxygen species
UR - http://www.scopus.com/inward/record.url?scp=85087053407&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85087053407&partnerID=8YFLogxK
U2 - 10.1016/j.jphotochem.2020.112621
DO - 10.1016/j.jphotochem.2020.112621
M3 - Article
AN - SCOPUS:85087053407
SN - 1010-6030
VL - 400
JO - Journal of Photochemistry and Photobiology A: Chemistry
JF - Journal of Photochemistry and Photobiology A: Chemistry
M1 - 112621
ER -